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  • Javascript: Onload if checkbox is checked, change li class

    - by BoDiE2003
    I have this code on javascript side: function changeSelectionStyle(id) { if(document.getElementById(id).className != 'yes'){ document.getElementById(id).className = 'yes'; } else{document.getElementById(id).className = '';} } And this on html: <ul> <li id="selectedAuthorities-4_1li" class=""> <input type="checkbox" id="selectedAuthorities-4_1" name="selectedAuthorities" value="ROLE_ADD_COMMENT_TO_CV" checked="checked" onload="changeSelectionStyle(this.id + 'li');" onclick="changeSelectionStyle(this.id + 'li'); checkFatherSelection(this.id);"> <a href="#" onclick="document.getElementById('selectedAuthorities-4_1').click(); return false;"> Agregar comentario <samp><b></b>Permite agregar comentario en el detalle.</samp> </a> </li> Well what I cant get work is when the checkbox is selected, on load, the JS should check it, and assign class="yes" to the li, here: <li id="selectedAuthorities-4_1li" class=""> What should I add to my original JS function to make that possible. Note that li ids are not static, they are dynamic, the html li id is generated.

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  • How can I lookup an attribute in any scope by name?

    - by Wai Yip Tung
    How can I lookup an attribute in any scope by name? My first trial is to use globals() and locals(). e.g. >>> def foo(name): ... a=1 ... print globals().get(name), locals().get(name) ... >>> foo('a') None 1 >>> b=1 >>> foo('b') 1 None >>> foo('foo') <function foo at 0x014744B0> None So far so good. However it fails to lookup any built-in names. >>> range <built-in function range> >>> foo('range') None None >>> int <type 'int'> >>> foo('int') None None Any idea on how to lookup built-in attributes?

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  • @PrePersist with entity inheritance

    - by gerry
    I'm having some problems with inheritance and the @PrePersist annotation. My source code looks like the following: _the 'base' class with the annotated updateDates() method: @javax.persistence.Entity @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) public class Base implements Serializable{ ... @Id @GeneratedValue protected Long id; ... @Column(nullable=false) @Temporal(TemporalType.TIMESTAMP) private Date creationDate; @Column(nullable=false) @Temporal(TemporalType.TIMESTAMP) private Date lastModificationDate; ... public Date getCreationDate() { return creationDate; } public void setCreationDate(Date creationDate) { this.creationDate = creationDate; } public Date getLastModificationDate() { return lastModificationDate; } public void setLastModificationDate(Date lastModificationDate) { this.lastModificationDate = lastModificationDate; } ... @PrePersist protected void updateDates() { if (creationDate == null) { creationDate = new Date(); } lastModificationDate = new Date(); } } _ now the 'Child' class that should inherit all methods "and annotations" from the base class: @javax.persistence.Entity @NamedQueries({ @NamedQuery(name=Sensor.QUERY_FIND_ALL, query="SELECT s FROM Sensor s") }) public class Sensor extends Entity { ... // additional attributes @Column(nullable=false) protected String value; ... // additional getters, setters ... } If I store/persist instances of the Base class to the database, everything works fine. The dates are getting updated. But now, if I want to persist a child instance, the database throws the following exception: MySQLIntegrityConstraintViolationException: Column 'CREATIONDATE' cannot be null So, in my opinion, this is caused because in Child the method "@PrePersist protected void updateDates()" is not called/invoked before persisting the instances to the database. What is wrong with my code?

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  • Using memory-based cache together with conventional cache

    - by Industrial
    Hi! Here's the deal. We would have taken the complete static html road to solve performance issues, but since the site will be partially dynamic, this won't work out for us. What we have thought of instead is using memcache + eAccelerator to speed up PHP and take care of caching for the most used data. Here's our two approaches that we have thought of right now: Using memcache on all<< major queries and leaving it alone to do what it does best. Usinc memcache for most commonly retrieved data, and combining with a standard harddrive-stored cache for further usage. The major advantage of only using memcache is of course the performance, but as users increases, the memory usage gets heavy. Combining the two sounds like a more natural approach to us, even though the theoretical compromize in performance. Memcached appears to have some replication features available as well, which may come handy when it's time to increase the nodes. What approach should we use? - Is it stupid to compromize and combine the two methods? Should we insted be focusing on utilizing memcache and instead focusing on upgrading the memory as the load increases with the number of users? Thanks a lot!

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  • Does anyone knows the algorithm how Facebook detects the images when adding a link

    - by Edelcom
    When you add a link to your Facebook page, after some processing, Facebook presents you a next/prev button to choose an image linked to the url your are inserting. Obviously, Facebook reads the html-page and displays the images found on the url you insert. Does anyone knows what algorithm Facebook uses to decide what images to show ? If I insert a link to : http://www.staplijst.be/lachende-wandelaars-aalter-aktivia-003.asp, only 11 images are detected. The one I want, the one at the top right corner, is not included in the list. If I insert a link to http://www.staplijst.be/stichting-kennedymars-rijsbergen-zundert-nederland-knblo-nl-81996.asp, 19 images are displayed (including the one I want (the one at the right top corner of the text area). Both pages are build using asp code but are functionally the same. I thought that it has something to do with the image size, but can't find any deciding factor there. I will investigate some furhter, because if I know what Facebook is looking for, I can make sure that the correct images are included on the page (since they are dynamic pages build with classic asp). But if anyone has any idea ? Help would be appreciated.

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  • wrapping user controls in a transaction

    - by Hans Gruber
    I'm working on heavily dynamic and configurable CMS system. Therefore, many pages are composed of a dynamically loaded set of user controls. To enable loose coupling between containers (pages) and children (user controls), all user controls are responsible for their own persistence. Each User Control is wired up to its data/service layer dependencies via IoC. They also implement an IPersistable interface, which allows the container .aspx page to issue a Save command to its children without knowledge of the number or exact nature of these user controls. Note: what follows is only pseudo-code: public class MyUserControl : IPersistable, IValidatable { public void Save() { throw new NotImplementedException(); } public bool IsValid() { throw new NotImplementedException(); } } public partial class MyPage { public void btnSave_Click(object sender, EventArgs e) { foreach (IValidatable control in Controls) { if (!control.IsValid) { throw new Exception("error"); } } foreach (IPersistable control in Controls) { if (!control.Save) { throw new Exception("error"); } } } } I'm thinking of using declarative transactions from the System.EnterpriseService namespace to wrap the btnSave_Click in a transaction in case of an exception, but I'm not sure how this might be achieved or any pitfalls to such an approach.

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  • Question about the evolution of interaction paradigm between web server program and content provider program?

    - by smwikipedia
    Hi experts, In my opinion, web server is responsible to deliver content to client. If it is static content like pictures and static html document, web server just deliver them as bitstream directly. If it is some dynamic content that is generated during processing client's request, the web server will not generate the conetnt itself but call some external proram to genearte the content. AFAIK, this kind of dynamice content generation technologies include the following: CGI ISAPI ... And from here, I noticed that: ...In IIS 7, modules replace ISAPI filters... Is there any others? Could anyone help me complete the above list and elabrate on or show some links to their evolution? I think it would be very helpful to understand application such as IIS, TomCat, and Apache. I once wrote a small CGI program, and though it serves as a content generator, it is still nothing but a normal standalone program. I call it normal because the CGI program has a main() entry point. But with the recenetly technology like ASP.NET, I am not writing complete program, but only some class library. Why does such radical change happens? Many thanks.

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  • Javascript tr click event with newly created rows

    - by yalechen
    I am very new to web development. I am currently using tablesorter jquery plugin to create a dynamic table, where the user can add and delete rows. I am having trouble with changing the background color of newly created rows upon clicking. It works fine with rows that are hard coded in html. Here is the relevant code: $(document).ready( function() { $('table.tablesorter td').click( function (event) { $(this).parent('tr').toggleClass('rowclick'); $(this).parent('tr').siblings().removeClass('rowclick'); }); } ) rowclick is a css class here: table.tablesorter tbody tr.rowclick td { background-color: #8dbdd8; } I have tried adding the following to my javascript function that adds a new row: var createClickHandler = function(newrow) { return function(event) { //alert(newrow.cells[0].childNodes[0].data); newrow.toggleClass('rowclick'); newrow.siblings().removeClass('rowclick'); }; } row.onclick = createClickHandler(row); The alert correctly displays the text in the first column of the row when I click the new row. However, my new rows do not respond to the css class. Anyone have any ideas? Thanks in advance.

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  • rich:editor ruins html?

    - by Ben
    Hi, Strange behaviour. I use rich:editor with these attributes: (Irrelevant data removed) HtmlEditor editor = new HtmlEditor(); editor.setValueExpression("value", ve); editor.setTheme("advanced"); editor.setValueExpression("viewMode", viewModeValueExpression); panel.getChildren().add(editor); Now my problem is that whenever I load a ready-made html text such as this (In source mode): <html lang="en" xml:lang="en"> <head> <title>Done</title> </head> <body style="direction: ltr; font-size: medium; color: #0000FF;"> <p>When the menu loads, navigate to and open Image Editor.</p> </body> </html> Change to VisualMode and then back to SourceMode, I see that the editor removed all of my html data and now the source mode is this: <p>When the menu loads, navigate to and open Chul Muzal.</p> Anyone knows why this happens? Thanks!!

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  • Prevent Text Input expanding in IE

    - by Caroline
    Hi, I am having a problem with an input field in IE. The code is for a portlet and widths need to be dynamic as the user can place the portlet on any of the three columns in the page which all have different widths. As always it works fine in FF but not in IE. In order to make the width dyanaic I have set width="100%". Data to populate the text input comes from a DB. When the page is rendered if there is a long URL the text input expands to fill the contents in IE but in FF it just stays the same width (ie 100% of the TD that it lives in). How can I stop IE from changing the width in order to fit the contents. Setting the width to a fixed width of 100px fixes the issue but I need to have the width as a percentage in order to accommodate the layout of the portlet wherever it is put in on the page. I have tried overflow:hidden and word-wrap:break-word but I cant get either to work. Here is my input code and style sheets <td class="right" > <input type="text" class="validate[custom[url]]" value="" id="linkText" name="communicationLink" maxlength="500" maxsize="100" /> </td> .ofCommunicationsAdmin input { font-family: "Trebuchet MS"; font-size: 11px; font-weight:normal; color:#333333; overflow:hidden; } .ofCommunicationsAdmin #linkText { overflow:hidden; width:100%; border:1px #cccccc solid; background:#F4F7ED top repeat-x; } .ofCommunicationsAdmin td.right { vertical-align: top; text-align: left; }

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  • Android - attach data to views

    - by Leonti
    Hi! In my application I create dynamic rows in table much as in this tutorial: http://en.androidwiki.com/wiki/Dynamically_adding_rows_to_TableLayout for(int i = startDay; i < startDay + 7; i++){ /* Create a TextView to be the row-content. */ TextView day = new TextView(this); day.setText(Integer.toString(i)); day.setLayoutParams(new LayoutParams( LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT)); day.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { Log.i("Listener: ", "Click"); } So now when I click on a TextView I can register click event, but how do I determine which TextView was clicked? Not just an object which I get with an event but data like which day number was clicked? Ideally I would want to have data attached to every view I create dynamically. Something like data() method in Javascript jQuery. Right now I can see only 1 way to solve this - while creating TextView add id with data and when clicked - get id back and parse it to get my data. But it strikes me as ugly approach. Is there a way to attach arbitrary data to android views?

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  • Winsock WSAAsyncSelect sending without an infinite buffer

    - by Xexr
    Hi, This is more of a design question than a specific code question, I'm sure I am missing the obvious, I just need another set of eyes. I am writing a multi-client server based on WSAAsyncSelect, each connection is made into an object of a connection class I have written which contains associated settings and buffers etc. My question concerns FD_WRITE, I understand how it operates: One FD_WRITE is sent immediately after a connection is established. Thereafter, you should send until WSAEWOULDBLOCK is received at which point you store what is left to send in a buffer, and wait to be told that it is ok to send again. This is where I have a problem, how large do I make this holding buffer within each connections object? The amount of time until a new FD_WRITE is received is unknown, I could be attempting to send a lot of stuff during this period, all the time adding to my outgoing buffer. If I make the buffer dynamic, memory usage could spiral out of control if for whatever reason, I am unable to send() and reduce the buffer. So my question is how do you generally handle this situation? Note I am not talking about the network buffer itself which winsock uses, but one of my own creation used to "queue" up sends. Hope I explained that well enough, thanks all!

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  • Why does my App.Config codebase not help .NET locate my assembly?

    - by pkolodziej
    I have the following client application and its corresponding config file: namespace Chapter9 { class Program { static void Main(string[] args) { AppDomain.CurrentDomain.ExecuteAssembly("AssemblyPrivate.exe"); } } } <configuration> <runtime> <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> <dependentAssembly> <codeBase href="file://C:\Users\djpiter\Documents\Visual Studio 2008\Projects\70536\AssemblyPrivate\bin\Debug\AssemblyPrivate.exe"/> </dependentAssembly> </assemblyBinding> </runtime> </configuration> The AssemblyPrivate.exe does not have a public key, nor is it located in the GAC. As far as I know, the runtime should parse the app.config file before looking for an assembly in the client app directory. The unhandled exception (wrapped for readability) is: Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'file:///C:\Users\djpiter\Documents\Visual Studio 2008\Projects\70536\Chapter9\bin\Debug\AssemblyPrivate.exe' or one of its dependencies. The system cannot find the file specified. Why it is not working? I need to use dynamic binding (not static). Kind Regards, PK

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  • Postback Removing Styling from Page

    - by Roy
    Hi, Currently I've created a ASP.Net page that has a dropdown control with autopostback set to true. I've also added color backgrounds for individual listitems. Whenever an item is selected in the dropdown control the styling is completely removed from all of the list items. How can I prevent this from happening? I need the postback to pull data based on the dropdown item that is selected. Here is my code. aspx file: <asp:DropDownList ID="EmpDropDown" AutoPostBack="True" OnSelectedIndexChanged="EmpDropDown_SelectedIndexChanged" runat="server"> </asp:DropDownList> <asp:TextBox ID="MessageTextBox" TextMode="MultiLine" Width="550" Height="100px" runat="server"></asp:TextBox> aspx.cs code behind: protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { GetEmpList(); } } protected void EmpDropDown_SelectedIndexChanged(object sender, EventArgs e) { GetEmpDetails(); } private void GetEmpList() { SqlDataReader dr = ToolsLayer.GetEmpList(); int currentIndex = 0; while (dr.Read()) { EmpDropDown.Items.Add(new ListItem(dr["Title"].ToString(), dr["EmpKey"].ToString())); if (dr["Status"].ToString() == "disabled") { EmpDropDown.Items[currentIndex].Attributes.Add("style", "background-color:red;"); } currentIndex++; } dr.Close(); } private void GetEmpDetails() { SqlDataReader dr = ToolsLayer.GetEmpDetails(EmpDropDown.SelectedValue); while (dr.Read()) { MessageTextBox.Text = dr["Message"].ToString(); } dr.Close(); } Thank You

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  • How to redirect a URL with GET variables in routes.rb without Rails stripping out the variable first?

    - by Michael Hopkins
    I am building a website in Rails to replace an existing website. In routes.rb I am trying to redirect some of the old URLs to their new equivalents (some of the URL slugs are changing so a dynamic solution is not possible.) My routes.rb looks like this: match "/index.php?page=contact-us" => redirect("/contact-us") match "/index.php?page=about-us" => redirect("/about-us") match "/index.php?page=committees" => redirect("/teams") When I visit /index.php?page=contact-us I am not redirected to /contact-us. I have determined this is because Rails is removing the get variables and only trying to match /index.php. For example, If I pass /index.php?page=contact-us into the below routes I will be redirected to /foobar: match "/index.php?page=contact-us" => redirect("/contact-us") match "/index.php?page=about-us" => redirect("/about-us") match "/index.php?page=committees" => redirect("/teams") match "/index.php" => redirect("/foobar") How can I keep the GET variables in the string and redirect the old URLs the way I'd like? Does Rails have an intended mechanism for this?

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  • What is the optimum way to secure a company wide wiki?

    - by Mark Robinson
    We have a wiki which is used by over half our company. Generally it has been very positively received. However, there is a concern over security - not letting confidential information fall into the wrong hands (i.e. competitors). The default answer is to create a complicated security matrix defining who can read what document (wiki page) based on who created it. Personally I think this mainly solves the wrong problem because it creates barriers within the company instead of a barrier to the external world. But some are concerned that people at a customer site might share information with a customer which then goes to the competitor. The administration of such a matrix is a nightmare because (1) the matrix is based on department and not projects (this is a matrix organisation), and (2) because in a wiki all pages are by definition dynamic so what is confidential today might not be confidential tomorrow (but the history is always readable!). Apart from the security matrix, we've considered restricting content on the wiki to non super secret stuff, but off course that needs to be monitored. Another solution (the current) is to monitor views and report anything suspicious (e.g. one person at a customer site having 2000 views in two days was reported). Again - this is not ideal because this does not directly imply a wrong motive. Does anyone have a better solution? How can a company wide wiki be made secure and yet keep its low threshold USP? BTW we use MediaWiki with Lockdown to exclude some administrative staff.

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  • Enumerating pixel formats for adaptors and modes with OpenGL

    - by Robinson
    I'm trying to code an OpenGL path for my 3D engine. The D3D path enumerates all device adaptors, all modes (by mode I mean bit depth, dimensions, available windowed, and refresh rate) for each adaptor and then all pixel formats available for the given mode and adaptor, along side certain useful caps (shader version, filter types, etc.). So, I have broadly got the following protected functions in the class: // Enumerate all back/front buffer combinations. virtual void EnumerateBackFrontBufferCombinations(CComPtr<IDirect3D9>& d3d9); // Enumerate all depth/stencil formats. virtual void EnumerateDepthStencilFormats(CComPtr<IDirect3D9>& d3d9); // Enumerate all multi-sample formats. virtual void EnumerateMultiSampleTypes(CComPtr<IDirect3D9>& d3d9); // Enumerate all device formats, i.e. dynamic, static, render target, etc. virtual void EnumerateMapFormats(CComPtr<IDirect3D9>& d3d9); // Enumerate all capabilities. virtual void EnumerateCapabilities(CComPtr<IDirect3D9>& d3d9); The adaptors are enumerated with EnumDisplayDevices, the modes (resolutions and refresh rates) are enumerated with EnumDisplaySettings, so this can be done for either GL or D3D. The other functions I'm not so sure about with OpenGL. What are the equivalents to the IDirect3D9's CheckDeviceType, CheckDeviceFormat, CheckDeviceMultiSampleType, CheckDepthStencilMatch? I know I can use DescribePixelFormat, given a DC, but you kind-of need to have created the window before you can use a DC with it, but you can't create the window correctly until you know what formats you're going to use. Any tips you can give me? Thanks.

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  • Using complex where clause in NHibernate mapping layer

    - by JLevett
    I've used where clauses previously in the mapping layer to prevent certain records from ever getting into my application at the lowest level possible. (Mainly to prevent having to re-write lots of lines of code to filter out the unwanted records) These have been simple, one column queries, like so this.Where("Invisible = 0"); However a scenario has appeared which requires the use of an exists sql query. exists (select ep_.Id from [Warehouse].[dbo].EventPart ep_ where Id = ep_.EventId and ep_.DataType = 4 In the above case I would usually reference the parent table Event with a short name, i.e. event_.Id however as Nhibernate generates these short names dynamically it's impossible to know what it's going to be. So instead I tried using just Id, from above ep_ where Id = ep_.EventId When the code is run, because of the dynamic short names the EventPart table short name ep_ is has another short name prefixed to it, event0_.ep_ where event0_ refers to the parent table. This causes an SQL error because of the . in between event0_ and ep_ So in my EventMap I have the following this.Where("(exists (select ep_.Id from [isnapshot.Warehouse].[dbo].EventPart ep_ where Id = ep_.EventId and ep_.DataType = 4)"); but when it's generated it creates this select cast(count(*) as INT) as col_0_0_ from [isnapshot.Warehouse].[dbo].Event event0_ where (exists (select ep_.Id from [isnapshot.Warehouse].[dbo].EventPart event0_.ep_ where event0_.Id = ep_.EventId and ep_.DataType = 4) It has correctly added the event0_ to the Id Was the mapping layer where clause built to handle this and if so where am I going wrong?

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  • How can I strip Python logging calls without commenting them out?

    - by cdleary
    Today I was thinking about a Python project I wrote about a year back where I used logging pretty extensively. I remember having to comment out a lot of logging calls in inner-loop-like scenarios (the 90% code) because of the overhead (hotshot indicated it was one of my biggest bottlenecks). I wonder now if there's some canonical way to programmatically strip out logging calls in Python applications without commenting and uncommenting all the time. I'd think you could use inspection/recompilation or bytecode manipulation to do something like this and target only the code objects that are causing bottlenecks. This way, you could add a manipulator as a post-compilation step and use a centralized configuration file, like so: [Leave ERROR and above] my_module.SomeClass.method_with_lots_of_warn_calls [Leave WARN and above] my_module.SomeOtherClass.method_with_lots_of_info_calls [Leave INFO and above] my_module.SomeWeirdClass.method_with_lots_of_debug_calls Of course, you'd want to use it sparingly and probably with per-function granularity -- only for code objects that have shown logging to be a bottleneck. Anybody know of anything like this? Note: There are a few things that make this more difficult to do in a performant manner because of dynamic typing and late binding. For example, any calls to a method named debug may have to be wrapped with an if not isinstance(log, Logger). In any case, I'm assuming all of the minor details can be overcome, either by a gentleman's agreement or some run-time checking. :-)

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  • InvalidCastException when getting Text from a Label referenced by dynamicaly built String, Fix?

    - by Chris
    NET Version: 3.5 Ok, I recieve an error (System.InvalidCastException was unhandled. Message="Unable to cast object of type 'System.Windows.Forms.Control[]' to type 'System.Windows.Forms.Label'.") when trying to get Text from a Label referenced by a dynamicly built string. Here's my situation; I have an array of 250 labels named l1 - l250. What I want to do is loop through them using this while statement: int c = 1; while (c < 251) { string k = "l" + c.ToString(); //dynamic name of Control(Label) object ka = Controls.Find(k, true); string ct = ((Label)ka).Text; //<<Error Occurs Here build = build + ct; c++; } and get the text value of each to build a string named build. I don't get any build errors, just this while debuging. While debuging I can go down to view my local variables. When looking through these, I can view the contents of object ka; it does contain the correct Text value of the correct Label I want to "access". I just don't understand how to get there. The text value is listed under "[0]" which is the only subcatagory for "ka".

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  • Multiple jQuery UI buttons with same ID

    - by Mark Nolan
    There might be a really simple solution to this question, but i just don't see it! I have a page with a list of items. every item has the same jquery ui button (its inside a dialog and adds that item to a list). i identify the item via the parenting DIV holding the DB id. So far so good... The Problem is only the first button on the list works! The second, third etc. buttons don't show any reaction at all. The buttons all have the same id - as the list is dynamic and the same action is triggered with every click. Only the parenting ID changes. Heres the display part: <div id="2"> <div id="56"> <button id="add-audio-file" class="ui-button ui-state-default ui-corner-all">betty_2.mp3</button> </div> </div> <div id="2"> <div id="57"> <button id="add-audio-file" class="ui-button ui-state-default ui-corner-all">betty_3.mp3</button> </div> </div> And here comes the js Part: $('#add-audio-file').click(function() { assetID = $(this).parent('div').attr('id'); pageID = $(this).parent('div').parent('div').attr('id'); $.post( "modules/portfolio/serialize.php", {id : pageID, assetid : assetID, do : "add-audio-file"}, function(data, textStatus, xhr) { $('#dialog-add-audio').dialog('close'); } ); }); I am using jquery 1.4.2 and jquery ui 1.8rc3 Any ideas?

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  • Web Shop Schema - Document Db

    - by Maxem
    I'd like to evaluate a document db, probably mongo db in an ASP.Net MVC web shop. A little reasoning at the beginning: There are about 2 million products. The product model would be pretty bad for rdbms as there'd be many different kinds of products with unique attributes. For example, there'd be books which have isbn, authors, title, pages etc as well as dvds with play time, directors, artists etc and quite a few more types. In the end, I'd have about 9 different products with a combined column count (counting common columns like title only once) of about 70 to 100 whereas each individual product has 15 columns at most. The three commonly used ways in RDBMS would be: EAV model which would have pretty bad performance characteristics and would make it either impractical or perform even worse if I'd like to display the author of a book in a list of different products (think start page, recommended products etc.). Ignore the column count and put it all in the product table: Although I deal with somewhat bigger databases (row wise), I don't have any experience with tables with more than 20 columns as far as performance is concered but I guess 100 columns would have some implications. Create a table for each product type: I personally don't like this approach as it complicates everything else. C# Driver / Classes: I'd like to use the NoRM driver and so far I think i'll try to create a product dto that contains all properties (grouped within detail classes like book details, except for those properties that should be displayed on list views etc.). In the app I'll use BookBehavior / DvdBehaviour which are wrappers around a product dto but only expose the revelent Properties. My questions now: Are my performance concerns with the many columns approach valid? Did I overlook something and there is a much better way to do it in an RDBMS? Is MongoDb on Windows stable enough? Does my approach with different behaviour wrappers make sense?

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  • Set "Start With" value for Oracle sequence dynamically

    - by Allan
    I'm trying to create a release script that can be deployed on multiple databases, but where the data can be merged back together at a later date. The obvious way to handle this is to set the sequence numbers for production data sufficiently high in subsequent deployments to prevent collisions. The problem is in coming up with a release script that will accept the environment number and set the "Start With" value of the sequences appropriately. Ideally, I'd like to use something like this: ACCEPT EnvironNum PROMPT 'Enter the Environment Number: ' --[more scripting] CREATE SEQUENCE seq1 START WITH &EnvironNum*100000; --[more scripting] This doesn't work because you can't evaluate a numeric expression in DDL. Another option is to create the sequences using dynamic SQL via PL/SQL. ACCEPT EnvironNum PROMPT 'Enter the Environment Number: ' --[more scripting] EXEC execute immediate 'CREATE SEQUENCE seq1 START WITH ' || &EnvironNum*100000; --[more scripting] However, I'd prefer to avoid this solution as I generally try to avoid issuing DDL in PL/SQL. Finally, the third option I've come up with is simply to accept the Start With value as a substitution variable, instead of the environment number. Does anyone have a better thought on how to go about this?

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  • ruby on rails one-to-many relationship

    - by fenec
    I would like to model a betting system relationship using the power of rails. so lets start with doing something very simple modelling the relationship from a user to a bet.i would like to have a model bet with 2 primary keys. here are my migrations enter code here class CreateBets < ActiveRecord::Migration def self.up create_table :bets do |t| t.integer :user_1_id t.integer :user_2_id t.integer :amount t.timestamps end end def self.down drop_table :bets end end class CreateUsers < ActiveRecord::Migration def self.up create_table :users do |t| t.string :name t.timestamps end end def self.down drop_table :users end end the models enter code here class Bet < ActiveRecord::Base belongs_to :user_1,:class_name=:User belongs_to :user_2,:class_name=:User end class User < ActiveRecord::Base has_many :bets, :foreign_key =:user_1) has_many :bets, :foreign_key =:user_2) end when i test here in the console my relationships I got an error enter code here u1=User.create :name="aa" = # u2=User.create :name="bb" = # b=Bet.create(:user_1=u1,:user_2=u2) *****error***** QUESTIONS: 1 How do I define the relationships between these tables correctly? 2 are there any conventions to name the attributes (ex:user_1_id...) thank you for your help

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  • Using memcache together with conventional cache

    - by Industrial
    Hi! Here's the deal. We would have taken the complete static html road to solve performance issues, but since the site will be partially dynamic, this won't work out for us. What we have thought of instead is using memcache + eAccelerator to speed up PHP and take care of caching for the most used data. Here's our two approaches that we have thought of right now: Using memcache on all<< major queries and leaving it alone to do what it does best. Usinc memcache for most commonly retrieved data, and combining with a standard harddrive-stored cache for further usage. The major advantage of only using memcache is of course the performance, but as users increases, the memory usage gets heavy. Combining the two sounds like a more natural approach to us, even though the theoretical compromize in performance. Memcached appears to have some replication features available as well, which may come handy when it's time to increase the nodes. What approach should we use? - Is it stupid to compromize and combine the two methods? Should we insted be focusing on utilizing memcache and instead focusing on upgrading the memory as the load increases with the number of users? Thanks a lot!

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